- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding resident species, migrant, and regular in winter. Dark-eyed Junco was an uncommon breeding species during the Minnesota Breeding Bird Atlas.
There are five subspecies of juncos, all with distinct characteristics that provide considerable misery for taxonomists. The subspecies that occurs in Minnesota, Junco h. hyemalis, breeds throughout the midwestern and northeastern United States and Canada west to Alaska. It integrates with J. h. carolinensis in the Appalachian Mountains from southern New York State to West Virginia (Figure 1). The highest densities of the Minnesota subspecies are found in the western United States and Canada (Figure 1).
Assigned a Continental Concern Score of 8/20 by Partners in Flight.
A permanent resident to short-distance migrant, the Dark-eyed Junco overwinters throughout the United States and parts of southern Canada south to northern Mexico.
Seeds, arthropods, waste grain, and some fruit primarily foraged from the ground.
Cup-nest in highly variable locations, but usually on or near the ground in roots, moss, or grasses.
Roberts (1932) emphasized a distribution in the northern coniferous forests. He described its southern extent from central Pine County northwest to Itasca Park and eastern Marshall County. He further stated the species was “found evenly distributed, nesting alike among the rocks and fallen needles under the pines on the upland and in the sphagnum moss beneath the Labrador tea of the spruce and cedar swamps of the lowlands.” He confirmed nesting in Aitkin, Marshall, Pine, and St. Louis Counties plus in Itasca Park. All confirmations were of nests with eggs or young, except in Pine County, which was labeled as “feeding young.”
Years later, Green and Janssen (1975) also labeled the junco’s distribution primarily in the northeastern and north-central regions but scarce among the western and southern margins of these regions. They included additional confirmed nesting in Carlton, Cook, and Lake Counties, plus an observation of two young birds in northern Chisago County in 1950. Several years later, Janssen (1987) suggested a more restricted breeding distribution south to northern Carlton and Crow Wing Counties. He also noted an extensive summer record in Otter Tail County in 1977 from June 2 to July 12. Along with Hertzel and Janssen (1998), he included confirmed nesting from 6 counties since 1970: Aitkin, Beltrami, Cook, Koochiching, Lake, and Lake of the Woods.
The Minnesota Biological Survey included 100 breeding observation locations and reinforced the junco’s primary distribution as northeastern Minnesota but also included potential breeding locations in northern Pine, northern Cass, eastern Marshall, and northern Roseau Counties (Minnesota Department of Natural Resources 2016).
The MNBBA included 241 records and all were confined to the northern portions of the Laurentian Mixed Forest Ecological Province, especially the northern tier of counties from eastern Roseau and Beltrami Counties to Cook County (Figure 2). Twelve confirmed nesting records were reported, with the only new county record from northeastern Itasca County (Figures 2 and 3; Table 1). Possible nesting was reported in Carlton, Cass, and Crow Wing Counties, at the southern extent of its breeding distribution in the state. Breeding observations were only reported in 3.3% (156/4,733) of the atlas blocks surveyed.
The MNBBA probability map identifies a very patchy distribution of the Dark-eyed Junco throughout northern and north-central Minnesota (Figure 4). Concentrations were predicted in the lowland coniferous forests in the Agassiz Lowlands Ecological Subsection of northern Beltrami, western Koochiching, and parts of Lake of the Woods Counties. In addition, pockets of moderate populations were predicted in northeastern Aitkin, and many areas of Lake and St. Louis Counties. Overall, the junco is not predicted to be found anywhere in Minnesota in high densities.
Roberts (1932) provided little evidence of breeding distribution changes in Minnesota; though he documented Dark-eyed Juncos feeding their young in Pine County. In addition, the record of young birds in northern Chisago County in 1950 suggested some nesting in that region of the state (Green and Janssen 1975). The MNBBA recorded no detections in the western counties of Clearwater or Marshall, places where the species had previously been detected. Certainly the difficulty in identifying the species by song may play a role in the lack of detections in this region, especially in distinguishing it from the more common Chipping Sparrow. However, the species’ white outer tail retrices are conspicuous, so observers are unlikely to have misidentified it if it had been present.
Cutright et al. (2006) reported breeding observations from southern Wisconsin in the early 1900s, and Brewer et al. (1991) reported possible breeding as far south as latitude 44o north in the central portion of the lower peninsula of Michigan, which is the same latitude as southeastern Minnesota. In their review of the species in North America, Nolan et al. (2002) provided little evidence of historical changes in the Dark-eyed Junco’s breeding distribution in North America, but Cadman et al. (1987) emphasized its decline from southern Ontario, where it nested in the late 1800s.
In Minnesota, its historical record remains unclear. Southern and western portions of Minnesota were primarily prairie-grasslands and deciduous forests, unsuitable habitat for the species. The extent of these habitats was more limited in the southern regions of Wisconsin, Michigan, and Ontario. The limited information provided by Roberts (1932) suggests the species may have nested in more southerly (Pine County) and western locations (Marshall County) than it does today, especially where conifer forests existed, but its breeding distribution is unlikely to have been substantially more extensive in Minnesota.
*Note that the definition of confirmed nesting of a species is different for Breeding Bird Atlas projects, including the definition used by the Minnesota Breeding Bird Atlas, compared with a more restrictive definition used by the Minnesota Ornithologists’ Union. For details see the Data Methods Section.